JPH06162826A - Composite material for wire cover - Google Patents

Abstract

PURPOSE:To provide a wire cover composite material excellent in insulating and fire retarding properties and in mechanical strength by employing a mixture of thermosetting resin and foamed vinylidene chloride resin particles as the main component thereof. CONSTITUTION:The essential components of a composite material for a wire cover are 1 to 90vol% thermosetting resin, such as epoxy resin and unsaturated polyester resin, and 10 to 99vol% foamed vinylidene resin particles comprising foamed beads made by impregnating with a foaming agent such as propane an amorphous vinylidene chloride copolymer composed of 10 to 85wt.% vinylidene chloride and a 15 to 90wt.% copolymerizable monomer. Further, the mixture having fillers such as fire-retarding material, reinforcing material, coloring agents and extending agents added thereto is packed in a predetermined mold and heated to 120 deg.C and higher to set the epoxy resin and a molding obtained is used as wire covering material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite material for covering electric wires such as insulated electric wires and optical fiber cables.

[0002]

2. Description of the Related Art Conventionally, as a material for covering electric wires, a covering material such as plastic has simply been used for electric wires. However, since there is a high demand for high-density signal transmission and the like, it is considered to improve the insulating property of the covering material. Has been done. In general, in order to improve the insulating property, a method is used in which a foam is used to increase the porosity to obtain an insulating layer having a low dielectric constant. A thermoplastic resin, in particular, a polyolefin resin in which a chemical foaming agent is kneaded and decomposed and foamed has been studied. However, it is difficult to obtain high foaming, and the foaming ratio is at most 2 to
Since it can be increased up to 3 times, the porosity is low and it is difficult to reduce the dielectric constant. Further, even if an attempt is made to increase the porosity by increasing the addition amount of the chemical foaming agent to obtain high foaming, the foam becomes non-uniform, and there is a problem that the capacitance is not constant.

As another method, there is one using a foam obtained by a physical foaming method in which a thermoplastic resin is impregnated with a gas such as hydrocarbon, chlorofluorocarbon, and nitrogen to foam.
However, since the mechanical strength of the foam itself is low and the material itself is flammable, it is difficult to use. Recently, a method of coating the surface of an electric wire with a glass balloon or a vinylidene chloride-based resin microballoon with another binder has been studied. However, since the foam has a single-cell structure, it is necessary to increase the addition amount in order to increase the porosity, which causes a problem that the mechanical strength of the coating material decreases.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of conventional products by using expanded particles, and provides a composite material for wire coating which is excellent in insulation, flame retardancy and mechanical strength. It is intended to be provided.

[0005]

In order to solve the above-mentioned problems, the present inventors have developed a general foamed vinylidene chloride resin foamed particle having excellent flame retardancy and mechanical strength in a general thermosetting resin. As a result of diligent studies on a composite material of the above, the present invention has been completed. That is, the present invention relates to an electric wire coating material containing a thermosetting resin and a foamy vinylidene chloride resin foamed particle as an essential component.

In the present invention, as the thermosetting resin,
Known examples include epoxy resins, unsaturated polyester resins, polyurethane resins, silicone elastomers, phenol resins, melamine resins and the like. In the present invention, the foamed vinylidene chloride resin particles are foamed particles obtained by foaming beads obtained by impregnating an amorphous vinylidene chloride copolymer with a foaming agent. An amorphous vinylidene chloride copolymer is 10% by weight of vinylidene chloride.
As described above, the copolymer is 85% by weight or less, and the copolymerizable monomer is 15% by weight or more and 90% by weight or less. If the vinylidene chloride content is less than 10% by weight, the strength will be reduced. When it exceeds 85% by weight, the vinylidene chloride copolymer is
It becomes crystalline and the foamability decreases.

The copolymerizable monomers include vinyl chloride, (meth) acrylonitrile, styrene, α-methylstyrene, and acrylic acid esters such as methyl acrylate, methacrylic acid esters such as methyl methacrylate, and N-phenylmaleimide. Such as N-
Substituted maleimide and the like can be mentioned. You may use these individually or in combination of 2 or more types.

The vinylidene chloride copolymer may have a crosslinked structure. The crosslinked structure makes the foam rich in closed cells and improves the foam moldability. Examples of the crosslinking agent include divinylbenzene, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate. You can

As the polymerization method, any known method can be used, for example, suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization and the like. A known radical initiator can be used as the polymerization initiator. As for the impregnation method, a direct impregnation method in which the foaming agent is directly contacted with the beads in a gaseous or liquid state, or a suspension in water in which the foaming agent is added to the slurry liquid of the beads and impregnated by contacting in water And a polymerization impregnation method in which a foaming agent is added during polymerization to impregnate it.

Examples of the blowing agent include aliphatic hydrocarbons such as propane, butane, isobutane and pentane, chlorinated hydrocarbons such as methyl chloride, ethyl chloride and methylene chloride, monochlorodifluoroethane and trifluoroethane,
Difluoroethane, dichlorotrifluoroethane, 1,1-
Dichloro-1 fluoroethane, 2,2-dichloro-1,
Fluorinated hydrocarbons such as 1,1 trifluoroethane, 1,1,1,2-tetrafluoroethane and mixtures thereof can be used.

As a method for obtaining foamed particles, multi-foamed foamed particles can be easily obtained by heating vinylidene chloride resin particles containing a foaming agent with a heating medium such as steam, hot water or hot air. The heating conditions are selected according to the target expansion ratio. The expansion ratio of the expanded beads used is preferably 10 to 80 times. The diameter of the foamed particles depends on the diameter of the electric wire to be coated, but is 0.1
mm to 8 mm can be used.

The composition ratio to be mixed is as follows: expanded vinylidene chloride resin particles 10 to 99% by volume, thermosetting resin 1 to
It is 90% by volume, and the ratio can be determined according to the required physical properties. Further, if necessary, a filler such as a flame retardant, a reinforcing material, a coloring agent, and a filler may be added. Examples of the flame-retardant material include antimony-based, phosphoric acid ester-based, halogen compounds, aluminum hydroxide, and other substances.

As an example of the method for molding the composite material for covering electric wires of the present invention, foamed vinylidene chloride resin particles and a thermosetting resin are mixed, and a filler is also added if necessary. After mixing thoroughly, fill the mold according to the purpose with this mixture,
The electric wire coating material can be obtained by curing the thermosetting resin. Further, the method of continuously molding the above method is preferable because the manufacturing cost is low.

Since the vinylidene chloride resin foamed particles are multifoamed foamed particles having a uniform foam, it is easy to impart insulation properties and the expansion ratio can be adjusted, so that the material can be set according to the purpose. Therefore, the composite material has excellent flame retardancy.
Moreover, since the adhesiveness with the thermosetting resin having high mechanical strength is excellent, the obtained composite material has high mechanical strength. Therefore, it is very suitable as a composite material for covering electric wires such as insulated electric wires and optical fiber cables.

[0015]

The present invention will be described in detail with reference to the following examples.

[0016]

Example 1 10% by volume of a mixture prepared by adding 10.8 parts by weight of diethylenetriamine as a curing agent to 100 parts by weight of an epoxy resin, a foaming ratio of 36 times, and a particle size of 0.5 mm.
0.8 mm foamed vinylidene chloride resin foam particles 9
Mix 0% by volume. The adjusted mixture is filled in a predetermined mold, and the epoxy resin is cured at a temperature of 120 ° C. The obtained molded body is used as a wire coating material.

An example in which an electric wire is coated with the composite material for electric wire coating of the present invention is shown in FIG.

[0018]

The composite material containing the thermosetting resin of the present invention and the expanded foamed vinylidene chloride resin particles as essential components is easy to improve the porosity, and therefore has excellent insulating properties Since it has excellent flammability and mechanical strength, it is suitable for composite materials for wire coating such as insulated wires and optical fiber cables.

[Brief description of drawings]

FIG. 1 is a schematic view of an example using a composite material for electric wire coating of the present invention.

[Explanation of symbols]

 1 Thermosetting Resin 2 Vinylidene Chloride Resin Expanded Particles 3 Electric Wire

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Claims (1)

[Claims] 1. A composite material for coating an electric wire, which comprises a thermosetting resin and expanded foamed vinylidene chloride resin particles as essential components.